Vapor deposition apparatus including a blocking gas flow generation unit

ABSTRACT

A vapor deposition apparatus in which a deposition process is performed by moving a substrate, the vapor deposition apparatus including a supply unit that injects at least one raw material gas towards the substrate, and a blocking gas flow generation unit that is disposed corresponding to the supply unit and generates a gas-flow that blocks a flow of the raw material gas.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This is a divisional application based on pending application Ser. No.13/795,399, filed Mar. 12, 2013, the entire contents of which is herebyincorporated by reference.

This application claims priority to and the benefit of Korean PatentApplication No. 10-2012-0131114, filed on Nov. 19, 2012, in the KoreanIntellectual Property Office, the entire disclosure of which isincorporated by reference herein.

BACKGROUND

1. Field

Embodiments relate to a vapor deposition apparatus, a method of forminga thin film using the same, and a method of manufacturing an organiclight-emitting display apparatus.

2. Description of the Related Art

Semiconductor devices, display devices, and other electronic devices mayinclude a plurality of thin films. Various methods may be used to formthe plurality of thin films.

SUMMARY

Embodiments are directed to a vapor deposition apparatus in which adeposition process is performed by moving a substrate, the vapordeposition apparatus including a supply unit that injects at least oneraw material gas towards the substrate; and a blocking gas flowgeneration unit that is disposed corresponding to the supply unit andgenerates a gas-flow that blocks a flow of the raw material gas.

The vapor deposition apparatus may further include a chamber toaccommodate the substrate, the supply unit, and the blocking gas flowgeneration unit therein.

The blocking gas flow generation unit may inject towards the supply unita blocking gas that contains an inert gas.

The blocking gas flow generation unit may inject towards the supply unitthe blocking gas that contains an inert gas when the substrate is notlocated in a region corresponding to the supply unit.

The blocking gas flow generation unit may include a plurality of slitsto inject the blocking gas.

The vapor deposition apparatus may further include a driving unit tomove the substrate.

The substrate may be placed on a stage and the driving unit may beconnected to the stage to move the stage.

The driving unit may be disposed to have a reciprocal movement alongguide rails.

The driving unit may include a first supporting member, a secondsupporting member, and a separation space that is defined as a spacebetween the first supporting member and the second supporting member.

The first supporting member and the second supporting member may bedisposed to reciprocally move along guide rails.

The blocking gas flow generation unit may be disposed to correspond tothe separation space while the driving unit is moving.

The supply unit may inject the raw material gas towards ground.

The supply unit may include a first injection unit that injects a firstraw material gas, a second injection unit that injects a second rawmaterial gas, and an exhaust unit.

The first injection unit may inject the first raw material gas in aradical type form to the substrate by generating plasma at a same timeas when the first raw material gas is injected.

Embodiments are also directed to a method of forming a thin film on asubstrate using a vapor deposition apparatus, the method includingperforming a deposition process on the substrate, the deposition processincluding injecting at least one raw material gas towards the substratewhile moving the substrate relative to a supply unit that injects the atleast one raw material gas; and blocking a flow of the raw material gasusing a gas flow generated by a blocking gas flow generation unit thatis disposed corresponding to the supply unit.

The blocking gas may contain an inert gas, and the blocking gas flowgeneration unit may inject the blocking gas towards the supply unit whenthe substrate is not located in a region corresponding to the supplyunit.

Embodiments are also directed to a method of manufacturing an organiclight-emitting display apparatus that includes a thin film formed on asubstrate, the method including performing a deposition process on thesubstrate using a vapor deposition apparatus, the deposition processincluding injecting at least one raw material gas towards the substratewhile moving the substrate relative to a supply unit that injects the atleast one raw material gas; and blocking a flow of the raw material gasusing a gas flow generated by a blocking gas flow generation unit thatis disposed corresponding to the supply unit.

The organic light-emitting display apparatus may include a firstelectrode, an intermediate layer that includes an organic light-emittinglayer, a second electrode, and an encapsulating layer, and thedeposition process may form the encapsulating layer.

The deposition process may form an insulating layer.

The deposition process may form a conductive film.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail example embodiments with reference to the attached drawings inwhich:

FIG. 1 is schematic drawing of a vapor deposition apparatus according toan embodiment;

FIG. 2A is a plan view of an upper surface of a blocking gas flowgeneration unit of FIG. 1, according to an embodiment;

FIG. 2B is a plan view of an upper surface of a blocking gas flowgeneration unit of FIG. 1, according to another embodiment;

FIG. 3 is a schematic perspective view of a vapor deposition apparatusaccording to another embodiment;

FIG. 4 is a lateral view of the vapor deposition apparatus of FIG. 3;

FIG. 5 is a cross-sectional view taken along a line V-V of FIG. 3;

FIG. 6 is a schematic cross-sectional view of an organic light-emittingdisplay apparatus manufactured using the vapor deposition apparatusaccording to an embodiment; and

FIG. 7 is a magnified view of a portion F of FIG. 6.

DETAILED DESCRIPTION

Example embodiments will now be described more fully hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the example embodiments to those skilled in the art.

In the drawing figures, dimensions may be exaggerated for clarity ofillustration. It will be understood that when an element is referred toas being “on” another element, it can be directly on the other element,or one or more intervening elements may also be present. It will also beunderstood that when an element is referred to as being “under” anotherelement, it can be directly under, or one or more intervening elementsmay also be present. It will also be understood that when an element isreferred to as being “between” two elements, it can be the only elementbetween the two elements, or one or more intervening elements may alsobe present. Like reference numerals refer to like elements throughout.

FIG. 1 is schematic drawing of a vapor deposition apparatus 100according to an embodiment. FIG. 2A is a plan view of an upper surfaceof a blocking gas flow generation unit 160 of FIG. 1, according to anembodiment. FIG. 2B is a plan view of an upper surface of a blocking gasflow generation unit 160′ of FIG. 1, according to another embodiment.

In the example embodiment shown in FIGS. 1, 2A, and 2B, the vapordeposition apparatus 100 includes a chamber 101, a supply unit 110, andthe blocking gas flow generation unit 160.

The chamber 101 may be connected to a pump (not shown) to control anambient or atmospheric pressure during a deposition process, and mayaccommodate all of a substrate 30, the supply unit 110, and the blockinggas flow generation unit 160 to protect them. Although not shown, thechamber 101 may include at least one doorway through which the substrate30 may move in and out.

The supply unit 110 supplies at least one gas so that a depositionprocess with respect to the substrate 30 may be performed.

The substrate 30 is disposed to be able to move in a direction indicatedby an arrow, that is, to have a left-right reciprocal movement, asindicated in FIG. 1. That is, the substrate 30 is moved by a drivingunit (not shown in FIG. 1) so that a deposition process may becontinuously performed. In particular, a deposition process, in whichone cycle includes processes being performed a number of times, may bereadily performed by one cycle of a deposition process by continuouslymoving the substrate 30.

The substrate 30 is disposed below the supply unit 110, and thus, thesupply unit 110 injects at least one gas towards the substrate 30, e.g.,in a direction towards ground.

The blocking gas flow generation unit 160 is disposed corresponding tothe supply unit 110 to inject a blocking gas G upwards. The blocking gasflow generation unit 160 includes a plurality of slits 161 to inject theblocking gas G. Thus, as depicted in FIG. 2A, the blocking gas flowgeneration unit 160 may include a plurality of slits 161. The slits maybe substantially linear, curved, having a shape similar to a circle,etc. As depicted in FIG. 2B, the blocking gas flow generation unit 160′according to another embodiment may include a plurality of linear typeslits 161′.

The blocking gas flow generation unit 160 is disposed to correspond tothe supply unit 110 to inject the blocking gas G in a counter directionto the direction of the raw material gas injected from the supply unit110. The blocking gas G may include an inert gas so that the blockinggas G does not react with the raw material gas and to prevent anyadverse affect on the deposition process.

The blocking gas flow generation unit 160 prevents the raw material gasinjected from the supply unit 110 from spreading by injecting theblocking gas G in a direction towards the supply unit 110. Inparticular, the blocking gas G prevents the raw material gas injectedfrom the supply unit 110 from contaminating a bottom surface 101A of thechamber 101.

In the vapor deposition apparatus 100 according to the currentembodiment, a deposition process may be performed by continuously movingthe substrate 30, and thus, an efficiency of the deposition process maybe increased.

While the substrate 30 is positioned at a location corresponding to thesupply unit 110, one or more gases may be simultaneously or sequentiallyinjected to the substrate 30 from the supply unit 110. Generally, if asubstrate is outside of a region where a supply unit injects rawmaterial gas, the raw material gas injected from the supply unit is notblocked by the substrate but is instead spread in the chamber, such thatthe raw material gas may reach the bottom surface of the chamber andcontaminate the bottom surface. However, according to the currentembodiment, the blocking gas flow generation unit 160 is disposed tocorrespond to the supply unit 110, and the blocking gas G is injectedfrom the blocking gas flow generation unit 160 towards the supply unit110. The blocking gas G may form a blocking gas flow, and thus, may actas a barrier when the raw material gas is injected from the supply unit110. Therefore, the movement of the raw material gas towards the bottomsurface 101A of the chamber 101 is reduced or prevented. Thus, in thecourse of a continuous deposition process while the substrate 30 ismoving, the contamination of the bottom surface 101A of the chamber 101by the raw material gas may be reduced or prevented.

The blocking gas flow generation unit 160 may inject the blocking gas Gin various ways, for example, may continuously inject the blocking gas Gtowards the supply unit 110 or optionally, may inject the blocking gas Gwhen the substrate 30 is outside of the region corresponding to thesupply unit 110.

FIG. 3 is a schematic perspective view of a vapor deposition apparatus200 according to another embodiment. FIG. 4 is a lateral view of thevapor deposition apparatus 200 of FIG. 3. FIG. 5 is a cross-sectionalview taken along a line V-V of FIG. 3.

In the example embodiment shown in FIGS. 3 through 5, the vapordeposition apparatus 200 includes a chamber 201, a supply unit 210, ablocking gas flow generation unit 260, a driving unit 230, and a stage220.

The chamber 201 may be connected to a pump (not shown) to control anambient or atmospheric pressure during a deposition process, and mayaccommodate the substrate 30, the supply unit 210, the blocking gas flowgeneration unit 260, and other members, so as to protect them. Althoughnot shown, the chamber 201 may include at least one doorway throughwhich the substrate 30 may move in and out.

The supply unit 210 supplies at least one gas towards the substrate 30to perform a deposition process with respect to the substrate 30. Thesupply unit 210 may be of various types, for example, as depicted inFIG. 5, the supply unit 210 may include a first injection unit 211, asecond injection unit 212, and an exhaust unit 213. The first injectionunit 211 may inject a first raw material, and the second injection unit212 may inject a second raw material.

An example deposition process that uses the supply unit 210 will now bebriefly described. A first layer that contains the first raw materialgas injected from the first injection unit 211 is formed by moving thesubstrate 30 to a position corresponding to the first injection unit211, and a second layer that contains the second raw material injectedfrom the second injection unit 212 is formed on the first layer bymoving the substrate 30 to a position corresponding to the secondinjection unit 212 to react with the first layer, and as a result, alayer that contains the first raw material gas and the second rawmaterial is formed on the substrate 30. At this point, residualby-product gases and surplus gases are exhausted through the exhaustunit 213. Also, although not shown, the first injection unit 211 mayinject the first raw material gas in a radical type form by generatingplasma when the first raw material gas is injected.

The substrate 30 may be disposed to be able to reciprocally move indirections indicated by the arrows, that is, M1 and M2 directions ofFIG. 3.

The substrate 30 is placed on the stage 220. A fixing member (not shown)such as a clamp (not shown) may further be included to stably place thesubstrate 30 on the stage 220.

The substrate 30 may be disposed below the supply unit 210, and thus,the supply unit 210 may inject at least one gas towards the substrate30, that is, towards the ground.

The driving unit 230 is disposed to be able to be connected to the stage220 below the stage 220. The substrate 30 that is placed on the stage220 moves through the driving unit 230. Thus, the driving unit 230 maymove in the directions M1 and M2 of FIG. 3, and as a result, thesubstrate 30 may have a reciprocal movement.

The driving unit 230 moves along guide rails 240, and thus, a horizontalstate of the driving unit 230 may be readily maintained, and also,vibration and shaking of the driving unit 230 may be prevented. As aresult, the substrate 30 may have a uniform reciprocal movement during adeposition process and a uniform characteristic of the deposited filmmay be provided.

The driving unit 230 may include a first supporting member 231, a secondsupporting member 232, and a separation space 233.

The first supporting member 231 and the second supporting member 232 aredisposed to move along the guide rails 240 as they are separated fromeach other, and are connected to the stage 220.

The separation space 233 is defined as a space between the firstsupporting member 231 and the second supporting member 232. Also, theseparation space 233 is separated from the guide rails 240.

The blocking gas flow generation unit 260 is disposed to correspond tothe supply unit 210 to be able to inject the blocking gas G upwards. Theblocking gas flow generation unit 260 includes a plurality of slits toinject the blocking gas G, and as described above, the slits may haveshape such as, e.g., a circular shape or a linear shape.

The blocking gas flow generation unit 260 is disposed to correspond tothe supply unit 210, and thus, injects the blocking gas G in a counterdirection to the raw material gas injected from the supply unit 210. Theblocking gas G may include an inert gas that does not react with a rawmaterial gas so as to prevent an effect to the deposition process.

Also, the blocking gas flow generation unit 260 may prevent the rawmaterial gas from spreading by injecting the blocking gas G towards thesupply unit 210. In particular, the blocking gas G may prevent a bottomsurface 201A of the chamber 201 from being contaminated by the rawmaterial gas injected from the supply unit 210.

In the vapor deposition apparatus 200 according to the currentembodiment, the efficiency of the deposition process may be increasedsince the deposition process is performed by a continuous movement ofthe substrate 30. Thus, the substrate 30 may be disposed on the stage220, and the stage 220 may be reciprocally moved by the driving unit230. At this point, since the driving unit 230 is guided by the guiderail 240, the driving unit 230 may be able to reciprocally move whilemaintaining a horizontal state and may precisely control the reciprocalmovement of the substrate 30.

The driving unit 230 includes the first supporting member 231, thesecond supporting member 232, and the separation space 233. The blockinggas flow generation unit 260 is disposed between the guide rails 240 tobe separated from the guide rails 240, and corresponds to the separationspace 233 of the driving unit 230 when the driving unit 230 is moved. Inthis manner, if the substrate 30 is outside of a region corresponding tothe supply unit 210, the contamination of an inner wall of the chamber201, in particular, the bottom surface 201A of the chamber 201, by theraw material gas injected from the supply unit 210 may be reduced orprevented.

Also, as described above, the first injection unit 211 of the supplyunit 210 may generate plasma when the first raw material gas isinjected. The movement of the substrate 30 may lead to a pressure changeat a periphery of the first injection unit 211 such that a state of theplasma may be rapidly changed, and thus, the deposition characteristicsmay be affected. In the current embodiment, by injecting the blockinggas G from the blocking gas flow generation unit 260 towards the supplyunit 210, reduction of the deposition characteristic may be avoided bypreventing a rapid change in atmospheric pressure at a periphery of thesupply unit 210, in particular, below the supply unit 210, even when thesubstrate 30 is located outside of the region of the supply unit 210.

FIG. 6 is a schematic cross-sectional view of an organic light-emittingdisplay apparatus 10 manufactured using the vapor deposition apparatusaccording to an embodiment. FIG. 7 is a magnified view of a portion F ofFIG. 6.

More specifically, FIGS. 6 and 7 show the organic light-emitting displayapparatus 10 manufactured by using the vapor deposition apparatuses 100and 200 described above.

The organic light-emitting display apparatus 10 is formed on thesubstrate 30. The substrate 30 may be formed of, e.g., a glass material,a plastic material, or a metal.

A buffer layer 31 is formed on the substrate 30 to provide a planarizedsurface and to prevent moisture and foreign materials from penetratingtowards the substrate 30.

A thin film transistor (TFT) 40, a capacitor 50, and an organiclight-emitting device 60 are formed on the buffer layer 31. The TFT 40includes an active layer 41, a gate electrode 42, and source/drainelectrodes 43. The organic light-emitting device 60 includes a firstelectrode 61, a second electrode 62, and an intermediate layer 63. Thecapacitor 50 includes a first capacitor electrode 51 and a secondcapacitor electrode 52.

The active layer 41, formed to a predetermined pattern, may be disposedon an upper surface of the buffer layer 31. The active layer 41 mayinclude an inorganic semiconductor material such as silicon, an organicsemiconductor material, or an oxide semiconductor material, and may beformed by doping a p-type dopant or an n-type dopant.

A gate insulating film 32 is formed on the active layer 41. The gateelectrode 42 is formed on the gate insulating film 32 to correspond tothe active layer 41. The first capacitor electrode 51 may be formed onthe gate insulating film 32 by using the same material used to form thegate electrode 42.

An interlayer insulating layer 33 covering the gate electrode 42 isformed, and the source/drain electrodes 43 are formed to contactpredetermined regions of the active layer 41 on the interlayerinsulating layer 33. The second capacitor electrode 52 may be formed onthe interlayer insulating layer 33 by using the same material used toform the source/drain electrodes 43.

A passivation layer 34 covering the source/drain electrodes 43 isformed, and an additional insulating layer may be further formed on thepassivation layer 34 to planarize the TFT 40.

The first electrode 61 is formed on the passivation layer 34. The firstelectrode 61 is formed to be electrically connected to one of thesource/drain electrodes 43. Afterwards, a pixel defining film 35covering the first electrode 61 is formed. After forming a predeterminedopening 64 in the pixel defining film 35, an intermediate layer 63 thatincludes an organic light-emitting layer is formed in a region definedby the opening 64. The second electrode 62 is formed on the intermediatelayer 63.

An encapsulating layer 70 is formed on the second electrode 62. Theencapsulating layer 70 may contain an organic material or an inorganicmaterial, and may have a structure in which the organic material and theinorganic material are alternately stacked.

The encapsulating layer 70 may be formed by using the vapor depositionapparatuses 100 and 200 according to embodiments. Thus, a desired layermay be formed by using the vapor deposition apparatuses 100 and 200 bymoving the substrate 30 on which the second electrode 62 is formed in achamber.

In particular, the encapsulating layer 70 includes an inorganic layer 71and an organic layer 72, and the inorganic layer 71 includes a pluralityof layers 71 a, 71 b, and 71 c, and the organic layer 72 includes aplurality of layers 72 a, 72 b, and 72 c. At this point, the layers 71a, 71 b, and 71 c of the inorganic layer 71 may be formed by using thevapor deposition apparatuses 100 and 200.

In other implementations, the buffer layer 31, the gate insulating film32, the interlayer insulating layer 33, the passivation layer 34, thepixel defining film 35, and/or other insulating layers may be formed byusing the vapor deposition apparatuses 100 and 200 according toembodiments.

Also, the active layer 41, the gate electrode 42, the source/drainelectrodes 43, the first electrode 61, the intermediate layer 63, thesecond electrode 62, and other various thin films may be formed by usingthe vapor deposition apparatuses 100 and 200 according to embodiments.

As described above, when the vapor deposition apparatuses 100 and 200according to embodiments are used, the characteristics of depositedfilms formed in the organic light-emitting display apparatus 10 may beincreased, and thus, the electrical characteristics and image qualitycharacteristics may be increased.

Also, thin films included in liquid crystal display (LCD) apparatusesand thin films included in various display apparatuses besides theorganic light-emitting display apparatus 10 may be formed by using thevapor deposition apparatuses 100 and 200 according to embodiments.

By way of summation and review, a vapor deposition method may be used toform a thin film in a device. The vapor deposition method uses one ormore gases as raw materials to form a thin film. The vapor depositionmethod includes a chemical vapor deposition (CVD) method, an atomiclayer deposition (ALD) method, and the like.

According to the ALD method, after a raw material is injected andpurged/pumped, a single layer or a composite layer is adsorbed to asubstrate, and then another raw material is injected and purged/pumped,so that a desired single or composite atomic layer is formed. Amongdisplay apparatuses, an organic light-emitting display apparatus isexpected to become a next generation display apparatus due to its wideviewing angles, high contrast, and fast response speeds. The organiclight-emitting display apparatus includes an intermediate layer havingan organic emission layer between first and second electrodes which faceeach other, and also includes one or more various thin films. Adeposition process may be used to form a thin film of the organiclight-emitting display apparatus. As the organic light-emitting displayapparatus is increased in size and is configured to have highdefinition, it may become difficult to deposit a large thin film with adesired characteristic. Also, there may be a limit in increasing anefficiency of a process of forming the large thin film.

As described above, embodiments relate to a vapor deposition apparatuswith which a deposition procedure may be efficiently performed and acharacteristic of a deposition film may be improved. Embodiments alsorelate to a method of forming a thin film using the vapor depositionapparatus, and a method of manufacturing an organic light-emittingdisplay apparatus. Embodiments may provide a vapor deposition apparatusthat may be used to efficiently perform a deposition process and toimprove a characteristic of a deposition film, a method of manufacturinga thin film using the vapor deposition apparatus, and a method ofmanufacturing an organic light-emitting display apparatus.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A vapor deposition apparatus in which adeposition process is performed by moving a substrate, the vapordeposition apparatus comprising: a supply unit that injects at least oneraw material gas towards the substrate; a driving unit to move thesubstrate, and a blocking gas flow generation unit that is disposedcorresponding to the supply unit and generates a gas-flow that blocks aflow of the raw material gas, the blocking gas flow generation unit isseparated from the supply unit by at least a region along a firstdirection, wherein the blocking gas flow generation unit injects ablocking gas in a direction counter to an injection direction of the rawmaterial gas from the supply unit and the substrate is movable by thedriving unit to traverse between the flow of the raw material gas and aflow of the blocking gas, wherein the substrate is movable between theblocking gas flow generation unit and the supply unit along a seconddirection intersecting the first direction, and wherein when thesubstrate is disposed between the flow of the raw material gas and theflow of the blocking gas flow, the blocking gas flow is directed to theopposite surface of the surface of the substrate facing the flow of theraw material gas, and when the substrate is not disposed between theflow of the raw material gas and the flow of the blocking gas flow, theblocking gas flow faces the flow of the raw material.
 2. The vapordeposition apparatus as claimed in claim 1, further comprising a chamberto accommodate the substrate, the supply unit, and the blocking gas flowgeneration unit therein.
 3. The vapor deposition apparatus as claimed inclaim 1, wherein the blocking gas contains an inert gas.
 4. The vapordeposition apparatus as claimed in claim 1, wherein the blocking gasflow generation unit injects towards the supply unit the blocking gasthat contains an inert gas when the substrate is not located in a regioncorresponding to the supply unit.
 5. The vapor deposition apparatus asclaimed in claim 1, wherein the blocking gas flow generation unitincludes a plurality of slits to inject the blocking gas.
 6. The vapordeposition apparatus as claimed in claim 1, wherein the substrate isplaced on a stage and the driving unit is connected to the stage to movethe stage.
 7. The vapor deposition apparatus as claimed in claim 1,wherein the driving unit includes a first supporting member, a secondsupporting member, and a separation space that is defined as a spacebetween the first supporting member and the second supporting member. 8.The vapor deposition apparatus as claimed in claim 7, wherein the firstsupporting member and the second supporting member are disposed toreciprocally move along the guide rails.
 9. The vapor depositionapparatus as claimed in claim 7, wherein the blocking gas flowgeneration unit is disposed to correspond to the separation space whilethe driving unit is moving.
 10. The vapor deposition apparatus asclaimed in claim 1, wherein the supply unit injects the raw material gastowards ground.
 11. The vapor deposition apparatus as claimed in claim1, wherein the supply unit includes a first injection unit that injectsa first raw material gas, a second injection unit that injects a secondraw material gas, and an exhaust unit.
 12. The vapor depositionapparatus as claimed in claim 11, wherein the first injection unitinjects the first raw material gas in a radical type form to thesubstrate by generating plasma at a same time as when the first rawmaterial gas is injected.